JP2019130550A - Rolling machine leveling setting method, rolling machine leveling setting device, and steel plate manufacturing method - Google Patents

Abstract

An object of the present invention is to provide a material to be rolled on the exit side of a rolling mill even when a material to be rolled after width reduction has a camber and a wedge generated due to a temperature deviation in a width direction and an off-center amount before width reduction. To prevent camber from occurring. A method of setting a leveling of a rolling mill according to the present invention includes the steps of: reducing a width of a material to be rolled by using a width reduction press having a die for rolling down the material to be rolled; A leveling setting method of a rolling mill for setting a leveling operation amount of each rolling mill when rolling a material to be rolled, the width of the material to be rolled before the width reduction, the width reduction amount, the camber amount after the width reduction. And the camber amount and leveling generated after rolling according to the off-center amount before the width reduction and the value of the temperature change from the width reduction press device to each rolling mill of the widthwise temperature deviation of the material to be rolled during the width reduction. A setting step of setting a leveling operation amount of each rolling mill according to a leveling influence coefficient of each rolling mill indicating a relationship with the amount. [Selection diagram] FIG.

Description

  The present invention relates to a leveling setting method for a rolling mill, a leveling setting device for a rolling mill, and a method for manufacturing a steel sheet.

  In general, in a hot rolling process, a material to be rolled that has been heated in a heating furnace is rolled down to a predetermined thickness by a rolling mill group after being rolled down by a rolling press machine. In the width reduction press device, it is known that cambers and wedges are generated on the material to be rolled due to the temperature deviation in the width direction of the material to be rolled and the off-center amount on the entry side of the width reduction press device. The width direction temperature deviation of the camber, wedge, and rolled material after width reduction, which is an asymmetric factor in the width direction, causes camber to be rolled on the rolled material in the rolling mill group and causes damage to equipment such as roll troughs and side guides. In addition, the yield and quality of the product and the operating rate of the line are reduced.

  From such a background, a technique for suppressing the occurrence of camber in a material to be rolled has been proposed. Specifically, in Patent Document 1, the longitudinal curvature of the slab is calculated, and the widthwise temperature deviation of the slab is obtained from the relationship between the longitudinal curvature of the slab and the widthwise temperature deviation of the slab. A technique for setting a leveling operation amount of a rolling mill according to a temperature deviation in the width direction of the slab is described. Patent Document 2 discloses a technique for setting a leveling operation amount of a rolling mill in accordance with the temperature and sheet width of the material to be rolled measured on the entry side of the width reduction press device and the width reduction amount of the width reduction press device. Is described. Furthermore, Patent Document 3 describes a technique for setting a leveling operation amount of a rolling mill according to a wedge measured on the exit side of a width reduction press device.

JP 2010-212230 A JP 2006-163894 A JP, 2006-182636, A

  However, the technique described in Patent Document 1 sets the leveling operation amount of the rolling mill in consideration of only the difference in deformation resistance in the width direction caused by the temperature deviation in the width direction of the slab before the start of rolling. For this reason, the technique of patent document 1 cannot be applied when the slab before the rolling start has a camber, especially when the camber is generated on the exit side of the width reduction press apparatus.

  On the other hand, in the technique described in Patent Document 2, it is necessary to measure the temperature deviation in the width direction of the material to be rolled. However, oxide scale and cooling water generated in a heating furnace, steam by descaling for removing oxide scale, and the like Therefore, it is difficult to accurately measure the temperature deviation in the width direction of the material to be rolled. For this reason, according to the technique described in Patent Document 2, it is difficult to suppress the occurrence of camber on the material to be rolled on the exit side of the rolling mill. Furthermore, in the technique described in Patent Document 2, the camber is generated due to factors other than the temperature deviation in the width direction such as the accuracy of the machine equipment such as the side guide and the press die on the exit side of the width reduction press device. It cannot be applied.

  Further, in the technique described in Patent Document 3, it is necessary to measure the width direction plate thickness distribution of the material to be rolled. However, the width direction plate thickness distribution of the material to be rolled having high temperature and an oxide scale is accurately and stably measured. It is difficult to measure well. For this reason, according to the technique described in Patent Document 3, it is difficult to suppress the occurrence of camber on the material to be rolled on the rolling mill exit side. Furthermore, the technique described in Patent Document 3 cannot be applied when the material to be rolled after width reduction has a camber.

  The present invention has been made in view of the above problems, and its object is to have a camber and a wedge that are generated due to the width direction temperature deviation and the off-center amount before width reduction of the material to be rolled after width reduction. Even if it is the case, it is providing the leveling setting method of a rolling mill and the leveling setting apparatus of a rolling mill which can suppress that a camber generate | occur | produces in a to-be-rolled material by the rolling mill delivery side.

  Another object of the present invention is to generate camber even when the steel sheet after width reduction has camber and wedge generated due to temperature deviation in the width direction and off-center amount before width reduction. It is providing the manufacturing method of the steel plate which can manufacture the steel plate with which suppression was carried out.

The leveling setting method for a rolling mill according to the present invention is a method for rolling a material to be rolled using a plurality of rolling mills after rolling the material to be rolled using a width rolling press device having a mold for rolling the material to be rolled in the width direction. A rolling mill leveling setting method for setting a leveling operation amount of each rolling mill when rolling a material, the width before width reduction of the rolled material, the width reduction amount, the camber amount after width reduction, and the width The amount of camber and leveling generated after rolling according to the off-center amount before rolling and the value in consideration of the temperature change from the width rolling press device to each rolling mill of the width direction temperature deviation ΔT of the rolled material at the time of rolling And a setting step for setting the leveling operation amount of each rolling mill according to the leveling influence coefficient γ _j (j is an identification number of the rolling mill) of each rolling mill.

  In the leveling setting method for a rolling mill according to the present invention, in the above invention, the setting step includes a width before width reduction of the material to be rolled, a width reduction amount, a camber amount after width reduction, and an off-center amount before width reduction. And a step of estimating a temperature deviation ΔT in the width direction of the material to be rolled at the time of width reduction.

In the leveling setting method for a rolling mill according to the present invention, in the above invention, the setting step calculates a width direction temperature deviation ΔT of the material to be rolled at the time of width reduction using the following formula (1), and the width direction temperature deviation By substituting ΔT and the leveling influence coefficient γ _j of each rolling mill into the following equation (2), the leveling operation amount of each rolling mill (leveling operation amount for the i-th rolled material of the j-th rolling mill) ΔLv _The step of calculating _j ⁱ is included.

Here, in Equation (1), Cam _SZP is the camber amount after the width reduction of the rolled material, y _C is the off-center amount before the width reduction of the rolled material, W is the width of the rolled material before the width reduction, ΔW Is the width reduction amount of the material to be rolled, α is a coefficient indicating the relationship between the camber amount and width direction temperature deviation ΔT caused by width reduction due to the width direction temperature deviation ΔT of the material to be rolled before width reduction, β denotes a coefficient indicating a relationship between the camber quantity and the off-center amount y _C caused by the width reduction due to off-center amount y _C before width reduction.

The leveling setting device for a rolling mill according to the present invention uses a plurality of rolling mills to reduce the width of the material to be rolled using a width reduction press device having a mold for reducing the material to be rolled in the width direction. A leveling setting device for a rolling mill that sets a leveling operation amount of each rolling mill when rolling a material, the width before width reduction of the material to be rolled, a width reduction amount, a camber amount after width reduction, and a width The amount of camber and leveling generated after rolling according to the off-center amount before rolling and the value in consideration of the temperature change from the width rolling press device to each rolling mill of the width direction temperature deviation ΔT of the rolled material at the time of rolling And a setting means for setting a leveling operation amount of each rolling mill according to the leveling influence coefficient γ _j (j is an identification number of the rolling mill) of each rolling mill.

  The method for manufacturing a steel sheet according to the present invention includes a step of manufacturing a steel sheet using the leveling setting method for a rolling mill according to the present invention.

  According to the leveling setting method of the rolling mill and the leveling setting device of the rolling mill according to the present invention, the material to be rolled after the width reduction includes the camber and the wedge generated due to the temperature deviation in the width direction and the off-center amount before the width reduction. Even if it has, it can suppress that a camber generate | occur | produces in a to-be-rolled material by a rolling mill delivery side.

  According to the method for producing a steel sheet according to the present invention, even if the material to be rolled after width reduction has camber and wedge generated due to the width direction temperature deviation and the off-center amount before width reduction. A steel plate in which the occurrence of camber is suppressed can be produced.

FIG. 1 is a schematic diagram showing a configuration of a hot rolling line to which a rolling mill leveling setting method according to an embodiment of the present invention is applied. FIG. 2 is a schematic diagram showing a configuration of a leveling setting device for a rolling mill according to an embodiment of the present invention. FIG. 3 is a schematic diagram for explaining the definition of the camber amount. FIG. 4 is a schematic diagram for explaining the definition of the wedge amount. FIG. 5 is a schematic diagram for explaining the definition of the leveling amount. FIG. 6 is a view showing the rolling mill exit-side camber amount in the conventional example and the present invention example. FIG. 7 is a view showing the rolling mill exit-side camber amount in the conventional example and the present invention example.

  Hereinafter, a leveling setting method for a rolling mill according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of hot rolling line]
First, with reference to FIG. 1, the structure of the hot rolling line to which the leveling setting method of the rolling mill which is one Embodiment of this invention is applied is demonstrated. However, the application range of the present invention is not limited to the hot rolling line shown in FIG.

  FIG. 1 is a schematic diagram showing a configuration of a hot rolling line to which a rolling mill leveling setting method according to an embodiment of the present invention is applied.

  As shown in FIG. 1, in a hot rolling line 1 to which a leveling setting method for a rolling mill according to an embodiment of the present invention is applied, a material to be rolled S such as a steel plate heated in a heating furnace 2 is reduced in width. After being reduced in width by the press device 3, the rough rolling mill group 4 is rolled to a predetermined thickness. And the to-be-rolled material S rolled in the rough rolling mill group 4 is further thinly rolled in the finish rolling mill group 5 and then water-cooled by the water-cooling device 7 in the run-out table 6 and wound in a coil shape by the coiler 8. .

[Leveling setting method of rolling mill]
Next, with reference to FIGS. 2-5, the leveling setting method of the rolling mill which is one Embodiment of this invention is demonstrated.

  The main factors for the occurrence of camber in the material to be rolled S after the width reduction are the temperature deviation in the width direction of the material to be rolled S and the off-center with respect to the press die. The temperature deviation in the width direction of the material to be rolled S is such that when the material to be rolled S is extracted from the heating furnace 2, the material to be rolled S is cooled from the extraction side by the outside air flowing into the heating furnace 2 by opening the extraction door. Caused by Moreover, the to-be-rolled material S from which length differs in the heating furnace 2 adjoins, and the width direction temperature deviation arises also when the heating state in a tip end part differs from the heating state in a longitudinal direction center part. In addition, when the material to be rolled S is subjected to width reduction in a state of being off-centered with respect to the press mold, uneven width reduction is caused on the left and right sides, and cambers and wedges are generated. On the other hand, the off-center with respect to the press die is generated by the accuracy of the mechanical equipment such as wear of the side guides and backlash in the width reduction press device 3. As a result of intensive studies, the inventors of the present invention have found that the camber after the width reduction occurs due to the temperature deviation in the width direction of the material to be rolled and the off-center before the width reduction. Further, the inventors of the present invention have found that the temperature deviation in the width direction of the material to be rolled can be calculated by measuring the camber amount after width reduction and the off-center amount before width reduction.

  On the other hand, the cause of the occurrence of camber in the material to be rolled S on the exit side of the rough rolling machine constituting the rough rolling mill group 4 includes the camber and wedge of the material to be rolled S generated in the width reduction press device 3. Further, the temperature deviation in the width direction of the material to be rolled S at the time of width reduction is not only a cause of camber generation at the time of width reduction but also a factor of camber generation in the roughing mill. For this reason, it is necessary to set the leveling operation amount in consideration of the temperature deviation in the width direction of the material S to be rolled.

  The present invention has been devised based on the above findings. Specifically, until now, without considering the influence of the camber and the wedge of the rolled material S generated after the width reduction due to the temperature deviation in the width direction during the width reduction of the rolled material and the off-center before the width reduction. Since the leveling operation amount of the rough rolling mill group 4 was set, it was insufficient to suppress the camber on the exit side of the rough rolling mill group 4. On the other hand, in this invention, the influence of the camber and wedge of the to-be-rolled material S and the width direction temperature deviation of the to-be-rolled material S which arise by width reduction with respect to the camber amount in the exit side of the rough rolling mill group 4 is considered. Thus, by setting the leveling operation amount of the rough rolling mill group 4, camber on the exit side of the rough rolling mill group 4 is suppressed. Hereinafter, the leveling setting method of the rolling mill which is one embodiment of the present invention will be described with reference to FIG.

  In the following description, the camber amount Cam is defined as the amount of bending in the sheet width direction with respect to the longitudinal direction of the material S to be rolled on the exit side of the rough rolling mill, as shown in FIG. Specifically, the camber amount is defined as the maximum value of the distance between the center position L1 in the width direction of the material to be rolled S on the exit side of the rough rolling mill 41 and the reference position L2 of the material to be rolled S. Further, as shown in FIG. 4, the wedge is a difference between the left and right plate thicknesses of the rolled material S after rolling, and the plate thickness h1 on one end side in the width direction after rolling and the plate thickness h2 on the other end side. The deviation can be defined as Further, as shown in FIG. 5, the leveling amount Lv is a reduction amount (a reduction level) between the axial ends of the pair of work rolls 41a and 41b constituting the rough rolling mill 41 that rolls the material S to be rolled. Defined as the difference.

As shown in FIG. 2, in the leveling setting method for a rolling mill according to an embodiment of the present invention, first, the leveling setting device 13 uses an off-center amount measuring device 11 installed on the entry side of the width reduction press device 3. Then, the off-center amount y _C of the material to be rolled S on the entry side of the width reduction press device 3 is measured. The off-center amount y _C may be measured in advance. Next, the leveling setting device 13 measures the camber amount Cam _SZP generated in the material S to be rolled by the width reduction using the camber meter 12 installed between the width reduction press device 3 and the rough rolling mill group 4. To do. Next, the leveling setting device 13 _compares the off-center amount y _{C, the} camber amount Cam _SZP , the width reduction amount ΔW and width W of the material S to be rolled in the width reduction press device 3, and the width direction temperature deviation ΔT of the material S to be rolled. By substituting the measured value into the following formula (1) indicating the relationship, the temperature deviation ΔT in the width direction of the material S to be rolled is calculated. The above formula (1) is derived from the knowledge that the camber amount after the width reduction occurs due to the temperature deviation in the width direction during the width reduction and the off-center amount before the width reduction.

  Here, in the formula (1), the coefficient α indicates the relationship between the camber amount generated by the width reduction due to the width direction temperature deviation ΔT of the material to be rolled S before the width reduction and the width direction temperature deviation ΔT. It is a coefficient. The coefficient β is a coefficient indicating the relationship between the camber amount caused by the width reduction and the off-center amount due to the off-center amount before the width reduction. The values of the coefficients α and β can be estimated in advance from actual manufacturing results in actual machines or estimated by numerical calculation.

Finally, the leveling setting device 13 uses the width direction temperature deviation ΔT of the material to be rolled S calculated by the formula (1), and each rolling which constitutes the rough rolling mill group 4 from the following formula (2). A leveling operation amount (leveling operation amount for the i-th material to be rolled S of the j-th rolling mill) ΔLv _j ⁱ is calculated and set. Accordingly, even when having a camber and wedge the rolled material S after width reduction occurs due to the width direction temperature deviation ΔT and off-center amount y _C, outlet side of the rough rolling mill group 4 Thus, the occurrence of camber in the material to be rolled S can be suppressed.

Here, in the formula (2), the coefficient γ _j (j is an identification number of the rolling mill) is a temperature from the width reduction press device 3 of the width direction temperature deviation ΔT of the material to be rolled S at the time of width reduction to each rolling mill. It is a leveling influence coefficient which shows the relationship between the camber amount generated after rolling and the leveling amount according to the value considering the change. The value of the coefficient γ _j can be estimated in advance from actual manufacturing results in an actual machine or can be estimated by numerical calculation.

[Example 1]
The present invention was verified in a hot rolling line having a width reduction press device having a die for reducing the material to be rolled in the width direction, and a four-high rolling mill comprising a work roll and a reinforcing roll. The rolling object was a slab of mild steel having a length of 6000 to 8000 mm, a thickness of 260 mm, and a width of 900 to 1500 mm, the width reduction amount in the width reduction press apparatus was 50 to 300 mm, and the plate thickness on the delivery side of the rolling mill was 190 to 200 mm. 100 slabs were investigated. In addition, as a conventional technique, a leveling amount that is set so that there is no difference in roll gap difference between the driving side and the working side when no load is applied before rolling is started, and the leveling amount is kept constant during rolling. The amount of camber was measured on the exit side. In the example of the present invention, the leveling setting of the rolling mill was performed using the coefficients in the equations (1) and (2) as α = 0.1, β = 10.0, and γ = 0.05, respectively. Further, the amount of off-center before width reduction was -20 mm, which was a value measured in advance. On the other hand, in the conventional example, leveling was set without considering the influence on the camber amount at the rolling mill exit side due to the temperature deviation in the width direction at the time of width reduction. 6 (a) and 6 (b) show the camber amount on the rolling mill exit side in the conventional example and the present invention example. As shown in FIG. 6 (a), in the conventional example, the standard deviation (1σ) of the camber amount on the delivery side of the rolling mill was about 22.2 mm. On the other hand, as shown in FIG. 6B, in the example of the present invention, the standard deviation of the camber amount at the rolling mill exit side is about 16.4 mm, and the camber amount can be reduced as compared with the conventional example. It was.

[Example 2]
The present invention was verified in a hot rolling line having a width reduction press device having a die for reducing the material to be rolled in the width direction, and a four-high rolling mill comprising a work roll and a reinforcing roll. The rolling object was a slab of mild steel having a length of 6000 to 9000 mm, a thickness of 260 mm, and a width of 900 to 1500 mm, the width reduction amount in the width reduction press apparatus was 50 to 200 mm, and the plate thickness on the delivery side of the rolling mill was 190 to 210 mm. 100 slabs were investigated. In addition, as a conventional technique, a leveling amount that is set so that there is no difference in roll gap difference between the driving side and the working side when no load is applied before rolling is started, and the leveling amount is kept constant during rolling. The amount of camber was measured on the exit side. In the example of the present invention, the leveling setting of the rolling mill was performed using the coefficients in the equations (1) and (2) as α = 0.1, β = 10.0, and γ = 0.05, respectively. Further, the off-center amount before the width reduction was -10 mm, which was a value measured in advance. On the other hand, in the conventional example, leveling was set without considering the influence on the camber amount at the rolling mill exit side due to the temperature deviation in the width direction at the time of width reduction. FIGS. 7A and 7B show the camber amount on the rolling mill exit side in the conventional example and the present invention example. As shown in FIG. 7 (a), in the conventional example, the standard deviation (1σ) of the camber amount on the delivery side of the rolling mill was about 19.1 mm. On the other hand, as shown in FIG. 7B, in the example of the present invention, the standard deviation of the camber amount at the rolling mill exit side is about 12.7 mm, and the camber amount can be reduced as compared with the conventional example. It was.

  The embodiment to which the invention made by the present inventors is applied has been described above, but the present invention is not limited by the description and the drawings that constitute a part of the disclosure of the present invention. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Hot rolling line 2 Heating furnace 3 Width reduction press apparatus 4 Rough rolling mill group 5 Finish rolling mill group 6 Run-out table 7 Water cooling apparatus 8 Coiler 11 Off-center quantity measuring machine 12 Camber meter 13 Leveling setting apparatus 41 Rough rolling mill 41a, 41b Work roll S Roll material

Claims (5)

Leveling operation of each rolling mill when rolling the material to be rolled using a plurality of rolling mills after rolling the material to be rolled using a width reduction press device having a mold for rolling the material to be rolled in the width direction. A leveling setting method for a rolling mill that sets an amount,
The width before the width reduction of the material to be rolled, the amount of camber after width reduction, the amount of off-center before width reduction, and the width reduction press device of the width direction temperature deviation ΔT that the material to be rolled has at the time of width reduction. According to the leveling influence coefficient γ _j (j is the identification number of the rolling mill) of each rolling mill indicating the relationship between the camber amount generated after rolling and the leveling amount according to the value considering the temperature change up to the rolling mill. A leveling setting method for a rolling mill, comprising a setting step for setting a leveling operation amount for each rolling mill.   The setting step uses a width before width reduction of the material to be rolled, a width reduction amount, a camber amount after width reduction, and an off-center amount before width reduction, and a temperature deviation in the width direction of the material to be rolled at the time of width reduction. The leveling setting method for a rolling mill according to claim 1, further comprising a step of estimating ΔT. In the setting step, the width direction temperature deviation ΔT of the material to be rolled is calculated using the following formula (1), and the width direction temperature deviation ΔT and the leveling influence coefficient γ _j of each rolling mill are expressed by the following formula ( The step of calculating a leveling operation amount of each rolling mill (leveling operation amount with respect to the i-th material to be rolled by the j-th rolling mill) ΔLv _j ⁱ by substituting in 2) is provided. The leveling setting method of the rolling mill described in 1.

Here, in Equation (1), Cam _SZP is the camber amount after the width reduction of the rolled material, y _C is the off-center amount before the width reduction of the rolled material, W is the width of the rolled material before the width reduction, ΔW Is the width reduction amount of the material to be rolled, α is a coefficient indicating the relationship between the camber amount and width direction temperature deviation ΔT caused by width reduction due to the width direction temperature deviation ΔT of the material to be rolled before width reduction, β denotes a coefficient indicating a relationship between the camber quantity and the off-center amount y _C caused by the width reduction due to off-center amount y _C before width reduction. Leveling operation of each rolling mill when rolling the material to be rolled using a plurality of rolling mills after rolling the material to be rolled using a width reduction press device having a mold for rolling the material to be rolled in the width direction. A leveling setting device for a rolling mill for setting an amount,
The width before the width reduction of the material to be rolled, the amount of camber after width reduction, the amount of off-center before width reduction, and the width reduction press device of the width direction temperature deviation ΔT that the material to be rolled has at the time of width reduction. According to the leveling influence coefficient γ _j (j is the identification number of the rolling mill) of each rolling mill indicating the relationship between the camber amount generated after rolling and the leveling amount according to the value considering the temperature change up to the rolling mill. A leveling setting device for a rolling mill, comprising setting means for setting a leveling operation amount of each rolling mill.   The manufacturing method of the steel plate characterized by including the step which manufactures a steel plate using the leveling setting method of the rolling mill of any one of Claims 1-3.

Images